Genetic variation forms the basis of all physical, chemical and biological diversity in plant and animal species. Natural and modified gene expressions are complex biological processes that can be observed for species over a wide range of environmental conditions. In plant agriculture, traditional field screening techniques which have been used for identifying germplasm accession and breeding lines are often based on field reactions to environmental stresses, as observed by way of crossing, hybridization, varietal separation, collection, and further testing. Unfortunately, the most commonly used field methods are usually labor intensive, as well as time consuming and expensive to carry out. In many cases, field trial data have lacked repeatability and have usually been inconclusive due to the varying environmental influences of different locations and different growing seasons.
Technological advances in molecular genetics can potentially provide new inroads to understanding genetic variance, and efficient ways of employing this knowledge can increase crop production. Crop improvement through tissue culture, leaf protoplast asexual reproduction, and even reproduction of DNA through cloning of plant cell nuclei all appear feasible given the current technological advances in this field. However, it is still the case that characterization of specific genetic attributes of particular plants and plant systems under stressed environmental conditions, as well as studies on the inheritability of particular traits, have been particularly difficult to carry out.
One physical parameter which can be studied quite readily is respiration, i.e., the exchange of gases, oxidation of organic molecules, etc. One instrument useful for measuring gases in a biological system is a respirometer. Use of a respirometer and other devices have allowed scientists to use calorimetry in order to study the physiology and heat production in various animals and plants, often in relation to energy metabolism. As yet, however, researchers have not been able to successfully use this information to screen plants for favorable genetic characteristics in particular environmental conditions. The coordination of factors such as crop yield maximization with respiratory efficiency or net photosynthesis rates in leaves, chloroplasts, or whole plants has yet to be successfully achieved. Further, the metabolic basis of genetics and environmental stress interactions also remain relatively unknown. At present there is no known standard single metabolic screening rate for determining genetic characteristics for such qualities as heat, drought, or salt tolerance among plants and plant cultivars.
It is thus highly desirable to develop a method for screening plants or plant strains which can use plant respiration so as to determine which plants are best suited for which environmental conditions. It is also desirable to have a system for metabolic testing of plants which subjects them to a wide range of various factors such as temperature, moisture, or salinity. It is further desired that such a system be able to simply and efficiently treat plants or plant parts in order to quickly and accurately detect, separate, and characterize genetic traits and genetic lines among or within plant cultivars.